Re: [Qemu-devel] [PATCH] configure: improve usbfs check

[Thomas Huth <thuth@redhat.com>]

On 2019-02-13 22:18, Thomas Petazzoni wrote:
> The current check to test if usbfs support should be compiled or not
> solely relies on the presence of <linux/usbdevice_fs.h>, without
> actually checking that all definition used by Qemu are provided by
> this header file.
> 
> With sufficiently old kernel headers, <linux/usbdevice_fs.h> may be
> present, but some of the definitions needed by Qemu may not be
> available.
> 
> This commit improves the check by building a small program that
> actually tests whether the necessary definitions are available.
> 
> In addition, it fixes a bug where have_usbfs was set to "yes"
> regardless of the result of the test.
> 
> Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
> ---
>  configure | 19 +++++++++++++++++--
>  1 file changed, 17 insertions(+), 2 deletions(-)
> 
> diff --git a/configure b/configure
> index 3d89870d99..799c8e3b08 100755
> --- a/configure
> +++ b/configure
> @@ -4266,10 +4266,25 @@ fi
>  # check for usbfs
>  have_usbfs=no
>  if test "$linux_user" = "yes"; then
> -  if check_include linux/usbdevice_fs.h; then
> +  cat > $TMPC << EOF
> +#include <linux/usbdevice_fs.h>
> +
> +#ifndef USBDEVFS_GET_CAPABILITIES
> +#error "USBDEVFS_GET_CAPABILITIES undefined"
> +#endif
> +
> +#ifndef USBDEVFS_DISCONNECT_CLAIM
> +#error "USBDEVFS_DISCONNECT_CLAIM undefined"
> +#endif
> +
> +int main(void)
> +{
> +    return 0;
> +}
> +EOF
> +  if compile_prog "" ""; then
>      have_usbfs=yes
>    fi
> -  have_usbfs=yes
>  fi
>  
>  # check for fallocate

Reviewed-by: Thomas Huth <thuth@redhat.com>